Current fears of antibiotic-resistant bacteria and other microbes as well as of bioterrorism have increased the importance of developing new ways to protect people from microbial infection. It is, for example, important to develop new materials for making clothing that can be more safely worn in contaminated environments. Such materials would be useful, for example, in hospitals and during military and civilian operations where bacterial contamination has occurred, or is expected.
In developing new antimicrobial compositions, it is important to discourage further antibiotic resistance. Ideally, therefore, novel antimicrobial compositions will function through non-specific, non-metabolic mechanisms.
For example, polycationic (quaternary ammonium) strings were developed in the laboratory of Robert Engel. See Fabian et al., Syn. Lett., 1007 (1997); Strekas et al., Arch. Biochem. and Biophys. 364, 129-131 (1999). These strings are reported to have antibacterial activity. See Cohen et al., Heteroat. Chem. 11, 546-555 (2000). Such strings may be attached to the surfaces of fabrics, rendering the surfaces antimicrobial. See, for example, U.S. Pat. No. 7,285,286.
It is also known to embed antimicrobial compounds in solid polymers. See U.S. patent application publication 2008/0300252.
Methods are also known that allow the coating of antimicrobial agents on surfaces. The coating may, however, wash or wear-off, causing the surface to be unprotected from microbes.
There is clearly a need for improved methods for making antimicrobial compositions and products. Ideally, the compositions and products do not lead to bacterial resistance, and the antimicrobial property is stable to multiple washes, especially to machine laundering.
In this invention, the inventors have developed new and more effective methods for surface modification to render surfaces antimicrobial with extended durability.